"""列表转字符串"""
def join(data: list, splitChar: str):
    fst = True
    retStr = ''
    for d in data:
        if fst is not True:
            retStr += splitChar
        else:
            fst = False
        retStr += str(d)
    return retStr


def is_number(str):
    pass


def is_class(obj):
    pass





